NASA's Galileo space probe, which revolutionised scientists'
understanding of Jupiter and its moons, has made its final transmission
as the US space agency sent it plunging to destruction in the distant planet's
atmosphere.

The end of Galileo's 14-year mission gives NASA a chance
to showcase the successes of its unmanned space probes, even as the agency
faces widespread criticism over the Columbia space shuttle disaster.

The Galileo probe beamed rare data about the Jovian atmosphere
back to Earth in its last minutes.

The last transmission was received at 5:40am AEST, slightly
more than two minutes earlier than expected.

One measurement NASA is particularly keen to get could
confirm whether rocky debris orbits Jupiter.

However, the craft did not have much time to obtain such
readings before it burst into Jupiter's deeper atmosphere at 48.2 kilometres
per second.

"It has been a fabulous mission for planetary science,
and it is hard to see it come to an end," Claudia Alexander, Galileo
project manager at NASA's Jet Propulsion Laboratory, in California, said
earlier this week.

"After traversing almost three billion miles and
being our watchful eyes and ears around Jupiter, we're keeping our fingers
crossed that... Galileo will still give us new information about Jupiter's
environment."

"This is a very exciting time for us as we draw
to a close on this historic mission and look back at its science discoveries.
Galileo taught us much about Jupiter but there is still much to be learned
and for that, we look with promise to future missions," Charles Elachi,
director of the JPL, said recently.

Galileo, which has circled Jupiter 34 times, was sent
plunging into its atmosphere rather than risking a collision with Europa,
one of Jupiter's four principal moons.

One of Galileo's discoveries was that Europa likely has
an underground ocean.

NASA technicians feared that Galileo could contaminate
that ocean with microbes carried from Earth if it collided with Europa,
and thus affect a potential source of life and future scientific discovery.

Galileo was named after 17th Century Italian astronomer
Galileo Galilei, who discovered Jupiter's four key moons.

The probe also discovered oceans on Ganymede and Callisto
as well as volcanic activity on Jupiter's fourth moon, Io.

Launched in October 1989, Galileo arrived at Jupiter
in December 1995.

It took about 14,000 pictures during its lifetime. It
was the first spacecraft to pass near an asteroid, and the first to discover
a moon of an asteroid.

It was also the first spacecraft to directly measure
with a probe the atmosphere of Jupiter, the largest planet in the Earth's
solar system, and was the first to carry out long-term observations from
orbit.